So many video formats available and so video conversions from one format to another is always an essential which lead to making of several softwares for the conversion purpose. One of the such paid software which performs the function of video & audio conversion is Daniusoft Video Converter and it has been review here to give you a proper idea of what exactly this software is capable of doing.
Daniusoft Video Converter supports many input and output formats, almost now required for any paid software and it does have that. The possible conversion possible are video to video, video to audio and audio to audio.
This is how the Daniusoft Video Converter main window looks like:
Just like the other software Daniusoft Video Converter is a straightforward and easy to use software such that a normal user can also work on it. It can convert videos among MPEG, WMV, AVI to known popular formats like MP4, 3GP, ASF, MOV, M4V, MPG, VOB, MKV, MP4, MP2, FLV, MPEG, AAC, RM, RMVB, DAT, to standard and HD Video like MOV, SWF, VOB, AVI, DV, 3GP, 3G2, FLV, M4V, WMV and other HD formats. Output devices supports includes videos of iPod Nano 5G, TOuch 3G, Apple TV, ZUne HD, PSP, PS3, Xbox, Xbox 360, includes latest mobiles like Blackberry, Android and windows mobile like Pocket PC, Dell Axim X51, HP iPaq HW6500 etc., This means that conversions from HD videos to HD Videos.
The functions of Daniusoft Video Converter are
Supports many input and output formats
Supports Batch Processing
Allows users to do advanced video editing like crop, add watermark etc.,
Merge multiple files together
Supports almost all portable players like iPod, iPhone, Android Phone etc.,
User defined professional output formats settings
Capture pictures from video to save as wallpaper
There is some basic requirements to install this software. Daniusoft Video Converter supports Windows 2000, 2003, XP, Vista and Windows 7 with minimum amount of RAM required is 512 MB. File size of the software is 9.56 MB and priced at $35.95.

I think you can find a converter for free if you would search properly. Go to Cnet use Freeware in the licence drop down box.